﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpDesignPattern.BehavioralDesignPattern._10_State
{
    public class _1_Pure_State
    {

        void Invoke_Oure_State(string[] args)
        {
            // 开一个新的账户
            Account account = new Account("Learning Hard");

            // 进行交易
            // 存钱
            account.Deposit(1000.0);
            account.Deposit(200.0);
            account.Deposit(600.0);

            // 付利息
            account.PayInterest();

            // 取钱
            account.Withdraw(2000.00);
            account.Withdraw(500.00);

            // 等待用户输入
            Console.ReadKey();
        }


        // 账户类
        public class Account
        {
            public State State { get; set; }
            public string Owner { get; set; }
            public Account(string owner)
            {
                this.Owner = owner;
                this.State = new SilverState(0.0, this);
            }

            // 余额
            public double Balance { get { return State.Balance; } }

            // 存钱
            public void Deposit(double amount)
            {
                State.Deposit(amount);
                Console.WriteLine("存款金额为 {0:C}——", amount);
                Console.WriteLine("账户余额为 =:{0:C}", this.Balance);
                Console.WriteLine("账户状态为: {0}", this.State.GetType().Name);
                Console.WriteLine();
            }

            // 取钱
            public void Withdraw(double amount)
            {
                State.Withdraw(amount);
                Console.WriteLine("取款金额为 {0:C}——", amount);
                Console.WriteLine("账户余额为 =:{0:C}", this.Balance);
                Console.WriteLine("账户状态为: {0}", this.State.GetType().Name);
                Console.WriteLine();
            }

            // 获得利息
            public void PayInterest()
            {
                State.PayInterest();
                Console.WriteLine("Interest Paid --- ");
                Console.WriteLine("账户余额为 =:{0:C}", this.Balance);
                Console.WriteLine("账户状态为: {0}", this.State.GetType().Name);
                Console.WriteLine();
            }
        }



        // 抽象状态类
        public abstract class State
        {
            // Properties
            public Account Account { get; set; }
            public double Balance { get; set; } // 余额
            public double Interest { get; set; } // 利率
            public double LowerLimit { get; set; } // 下限
            public double UpperLimit { get; set; } // 上限

            public abstract void Deposit(double amount); // 存款
            public abstract void Withdraw(double amount); // 取钱
            public abstract void PayInterest(); // 获得的利息
        }

        #region 具体状态类
        // Red State意味着Account透支了
        public class RedState : State
        {
            public RedState(State state)
            {
                // Initialize
                this.Balance = state.Balance;
                this.Account = state.Account;
                Interest = 0.00;
                LowerLimit = -100.00;
                UpperLimit = 0.00;
            }

            // 存款
            public override void Deposit(double amount)
            {
                Balance += amount;
                StateChangeCheck();
            }
            // 取钱
            public override void Withdraw(double amount)
            {
                Console.WriteLine("没有钱可以取了！");
            }

            public override void PayInterest()
            {
                // 没有利息
            }

            private void StateChangeCheck()
            {
                if (Balance > UpperLimit)
                {
                    Account.State = new SilverState(this);
                }
            }
        }

        // Silver State意味着没有利息得
        public class SilverState : State
        {
            public SilverState(State state)
                : this(state.Balance, state.Account)
            {
            }

            public SilverState(double balance, Account account)
            {
                this.Balance = balance;
                this.Account = account;
                Interest = 0.00;
                LowerLimit = 0.00;
                UpperLimit = 1000.00;
            }

            public override void Deposit(double amount)
            {
                Balance += amount;
                StateChangeCheck();
            }
            public override void Withdraw(double amount)
            {
                Balance -= amount;
                StateChangeCheck();
            }

            public override void PayInterest()
            {
                Balance += Interest * Balance;
                StateChangeCheck();
            }

            private void StateChangeCheck()
            {
                if (Balance < LowerLimit)
                {
                    Account.State = new RedState(this);
                }
                else if (Balance > UpperLimit)
                {
                    Account.State = new GoldState(this);
                }
            }
        }


        // Gold State意味着有利息状态
        public class GoldState : State
        {
            public GoldState(State state)
            {
                this.Balance = state.Balance;
                this.Account = state.Account;
                Interest = 0.05;
                LowerLimit = 1000.00;
                UpperLimit = 1000000.00;
            }
            // 存钱
            public override void Deposit(double amount)
            {
                Balance += amount;
                StateChangeCheck();
            }
            // 取钱
            public override void Withdraw(double amount)
            {
                Balance -= amount;
                StateChangeCheck();
            }
            public override void PayInterest()
            {
                Balance += Interest * Balance;
                StateChangeCheck();
            }

            private void StateChangeCheck()
            {
                if (Balance < 0.0)
                {
                    Account.State = new RedState(this);
                }
                else if (Balance < LowerLimit)
                {
                    Account.State = new SilverState(this);
                }
            }
        }
        #endregion

    }
}
